Field
This disclosure is generally related to the field of data storage. More specifically, this disclosure is related to a method and system for a high-priority read based on an in-place suspend/resume write.
Related Art
The proliferation of the Internet and e-commerce continues to create a vast amount of digital content. Various storage systems have been created to access and store such digital content. In a standard storage system, a server may store data in a non-volatile memory, such as NAND flash component. A NAND flash typically includes multiple dies, where a single die can include a hierarchy of multiple plane, blocks, and pages. Data is written to and read from a page-level unit. A typical write operation to a NAND page can occupy an entire page buffer of the involved NAND die. As a result, a read request (e.g., a read operation) received during an ongoing write operation cannot begin or complete until the ongoing write operation is completed. That is, if a read operation is requested for the same die on which a write operation is currently being performed, the read operation must wait until the write operation is completed. Thus, the latency involved in performing the read operation on the die is dependent on completion of an ongoing write operation on the same NAND die.
Writing data to a page may require approximately several milliseconds, while reading data from a page may require only hundreds of microseconds. Thus, a read operation results in a higher latency from a delayed start in waiting for completion of an ongoing write operation, where the delay may be on the order of milliseconds. Given both the increasing density of current NAND dies and the decreasing size of computer components in general, a read operation may result in a hit on the same NAND die on which an ongoing write operation is being performed, thus resulting in a higher latency. This higher latency can decrease the efficiency of a storage system.